It was the home side who seized an early lead, with the visitors, who had already had a Shane Grady touchdown chalked off by the video referee, largely the authors of their own misfortune with some crucial unforced errors.
A crazy offload from Dan Fleming 10 metres from his own line paved the way for Weller Hauraki’s opening try, with Krisnan Inu converting.
And when a mix up between Will Sharp and James Woodburn-Hall, both players going for Finn’s kick, saw the ball end up on the floor, Inu trampled a couple of defenders to score in the corner, with the missed conversion leaving Fax trailing 10-0 inside the first quarter.
Slowly, Fax were finding their feet and they finally cracked their hosts five minutes before the break.
Scott Murrell was the architect, finding Woodburn-Hall with a neat inside ball and the Londoner barrelling over a couple of defenders to score.
Grady converted against his hometown club for 10-6 and the visitors kept the pressure on until the break.
It was Widnes who opened the second half scoring through Patrick Ah Van, frustratingly from more errors – Saltonstall turning the ball over and Ben Heaton failing to nail his man – with Inu’s sideline kick putting them 16-6 up.
When Inu completed his hat-trick from an Ah Van knock down and converted again, the Vikings were home and hosed at 22-6 with 17 minutes remaining.
Fax did get some reward for their endeavour when Woodburn-Hall’s break created the position for Heaton to put Saltonstall over in the corner, Murrell converting to make it 22-12.
But it was Widnes who sealed the points with Ah Van’s last minute try, maintaining their tenuous survival hopes.
Widnes: Mellor; Ah Van, Inu, Runciman, Buckley; Lyons, Finn; Gubb, White, Houston, Hauraki, Hansen, Leuluai. Substitutes: Walker, Chapelhow, Olbison, Wilde
Halifax: Sharp; Saltonstall, Heaton, Butler, Woodburn-Hall; Murrell, Johnston; Fleming, Kaye, Fairbank, Tangata, Grady, Davies. Substitutes: Jones, Moore, Cooper, Maher
Referee: G. Hewer.